A positive H. pylori antibody assay generally indicates a previous or ongoing H. pylori infection. H. pylori is a microaerobic bacterium that can infect and stimulate the body to produce IgM, IgG and IgA type antibodies. Specific IgG and IgA antibodies can be detected in the blood, gastric juice and saliva of infected individuals, suggesting the possibility of upper gastrointestinal tract diseases such as chronic gastritis, peptic ulcer, and possibly gastric cancer. If the test reveals positive for H. pylori, further tests are needed to determine if treatment is needed. It is generally recommended that patients be further tested with a carbon 13 or carbon 14 breath test to determine if H. pylori infection is indeed present. If the breath test is positive, the patient is advised to undergo a gastroscopy immediately to clarify the diagnosis. After diagnosis, the patient is given oral quadruple therapy against H. pylori for 10-14 days. Generally, the commonly used quadruple therapy includes proton pump inhibitor + bismuth + two antibiotics, namely amoxicillin, clarithromycin, omeprazole and colloidal bismuth for combination therapy. A carbon 13 or carbon 14 breath test is redone after 4 weeks of discontinuation to clarify whether H. pylori has been completely cleared.